1. Field of the Invention
The present invention generally relates to an elevator controlling system. More specifically, the present invention is directed to an elevator controlling system for controlling elevators by employing a plurality of microcomputers (referred to as "controlling microcomputers) and also for communicating data among a console having a keyboard for entering the data and a display for displaying the data, and also the microcomputers in order to monitor control conditions.
2. Description of the Prior Art
Very recently, in elevator control apparatuses, most of sequence controls for the elevators have been performed under control of microcomputers. Also, motors functioning as power sources for the elevators have been controlled in a digital control manner, and therefore may be controlled by way of microcomputers.
Then, when all of the control operations required in the elevator systems have been executed under control of the controlling microcomputers, it is practically difficult to externally monitor the control conditions of the elevator. Then, to solve such a difficulty, the consoles have be utilized which include keyboards for entering data and displays for monitoring the data.
The consoles are connected to the controlling microcomputers via either the general-purpose transmission interface such as RS 232C, or the exclusively used interface, thereby operable as the terminals for the controlling microcomputers.
On the other hand, since a controlling microcomputer processes substantially all of the controls required for an elevator controlling system and therefore only one controlling microcomputer can hardly accept such a heavy load, a plurality of controlling microcomputers are prepared within a single elevator control apparatus.
Although either digital input/output apparatuses (DI/DO), or serial transmissions may be employed as the interfaces among plural controlling apparatuses, a parallel system bus, or a so-called "multi-bus" having higher data transmission speeds and higher expandabilities may be usually utilized.
In FIG. 1, there is shown an arrangement of a conventional elevator control system in which a plurality of controlling microcomputers are commonly connected to each other via a parallel system bus. That is, both one controlling microcomputer 1 and the other controlling microcomputer 2 commonly share the parallel system bus 3. Although not shown in detail, in the respective controlling microcomputers 1 and 2, a transmission interface unit 5, CPU (central processing unit) 12, ROM (read-only memory) 13, RAM (random access memory) 14, input/output devices (I/O) 15 and an interface unit 10 for the parallel system bus are commonly connected with each other by a local bus 9. In this figure, a console 4 is connected to the transmission interface unit 5, whereas the parallel system bus 3 is connected to the bus interface unit 10.
Since in this conventional elevator controlling apparatus with the above-described arrangement, there are provided the transmission interface units 5 within the respective controlling microcomputers 1 and 2, each of the controlling microcomputers 1, 2 per se can execute the processing operations required for monitoring the control conditions of the elevators. As a result, the console may merely function as a terminal unit with respect to the software for the monitoring purpose, so that various consoles may be utilized.
However, there is such a problem in the above-described elevator controlling apparatuses, that since the controlling microcomputers, for instance, 1 and 2 employ the transfer interface unit 5 respectively, when the maintenance or adjustment for the elevator is carried out while the console 4 is connected to one controlling microcomputer 1, and also the control states of the other controlling microcomputer 2 are wished to be monitored, an operator must disconnect this console 4 from the first controlling microcomputer 1 and then must connect it to the second controlling microcomputer 2, resulting in cumbersome maintenance work loads. Accordingly, easy and simple maintenance would be desired.
Furthermore, since the controlling microcomputers employing the own transmission interfaces having the same functions with each other, the more the number of controlling microcomputers is increased, the more a total quantity of such interfaces is similarly increased. This may cause costly elevator controlling apparatuses.